Nilfisk-Advance Advance SC750 ST

Service Manual: SC750, SC800, SC 750 ST, SC800 ST
Form Number 56043150 Page 121
Powering up the Drive Motor Controller:
This is the same as the “ST” models. See above secon.
Drive Motor Controller Inputs
To drive forward, the operator pushes on a drive paddle which rotates the Speed Control Potenometer inside the
paddle. A separate Speed Limit Potenometer is rotated to control the maximum speed.
The drive motor controller has internal “voltmeters” that are monitoring 2 inputs.
1. Drive Paddle Posion - To know when to move and which direcon.
2. Speed Limit - To know what the maximum speed should be.
The drive paddle Posion potenometer is fed 5 volts from the controller on one side of its resisve strip. The voltage
goes through the resisve strip and returns to baery negave inside the controller. The “wiper” inside the potenom-
eter will return a voltage back to the controller as a direcon request input. If the wiper is exactly in the middle, as it
should be when drive paddle is in the spring loaded posion, the return voltage will be ½ of the supply voltage (2.5v).
As the paddle is pushed forward, the wiper moves closer to the supply side, resulng in an increase in voltage. Volt-
age above 2.5v is interpreted as a forward request. The same input is also used for more or less speed. As the paddle is
pushed farther forward, the voltage will increase and it will be interpreted as a request for more speed in the forward di-
recon. (When the drive paddle is pulled back, the voltage will drop below 2.5v. and is interpreted as a reverse request).
The Speed Limit Potenometer is fed 5 volts from the controller on one side of its resisve strip. The voltage goes
through the resisve strip and returns to baery negave inside the controller. The “wiper” inside the potenometer will
return a voltage back to the controller as a speed request input. If the wiper is close to the supply side, the voltage will
be high (4.6v = Maximum speed request). If it is close to the baery negave return side, the voltage will be low (0.2v =
Minimum speed request).
The combinaon of the drive paddle posion potenometer input and the speed limit potenometer input allows the
operator to hold the paddle all the way forward for normal operaon while sll being able to adjust the travel speed.
Drive Motor Controller Outputs
• This is the same as the ST models. See secon above.